Microbiomes are also dynamic and subject to skewing, and these changes are increasingly associated with diseases including Crohn's disease, ulcerative colitis, obesity, and possibly depression. Antibiotic therapies alter microbiomes, often causing temporary dysfunction and sometimes resulting in diseases such as colitis. Since IC or CP/CPPS patients often have a history of urinary tract infection (UTI), they typically receive multiple courses of antibiotics. This therapeutic history of IC or CP/CPPS patients may have adverse consequences for two reasons. First, potential skewing of the gut microbiome may alter normal sensory and functional homeostatic mechanisms, contributing to pain and voiding dysfunction. Second, an altered gut microbiome may foster uropathogen reservoir expansion, and our preliminary data demonstrate urinary E. coli isolates can induce chronic pelvic pain persisting long after microbial clearance. Together these lines of reasoning raise the provocative possibility that microbiomes contribute to IC, CP/CPPS, and depression directly by supplying uropathogens or indirectly through organ crosstalk dysfunction. Therefore, is an altered gastrointestinal tract microbiome associated with IC, CP/CPPS, and/or depression? Our team marries core NIH and NIDDK missions, digestive diseases and kidney/urologic, to address this novel question with synergistic expertise in clinical diagnosis of IC, CP/CPPS, and depression, quantifying GI tract microbiomes, and neural mechanisms of microbe-induced pelvic pain. Stool samples will be analyzed by 16S rDNA sequence and in silico metagenome analyses to identify taxa, abundance, and function. Computational tools will be used to identify taxa amenable to rapid evaluation of stool. Stool, serum, and urine will be evaluated for small molecules specific to CPPS, and these putative mediators will be tested in mice for effects on pelvic pain and urinary function.